#!/bin/awk -f

BEGIN {
	i=0;
	data[0]=0;
	d=0;
	a=0;
	c=0;
	f=0;
	FS=":";
}

{
	a+=$2;
	c+=$3;
	da[i]=$2;
	ta[i]=$3;
	i++;

}


END{
	a/i=b
	b/i=d
	for(j=0;j<i;j++){
		m=(da[j]-b)*(ta[j]-d)
		f=m+f
		}
		cc=f/(i-1)
print "shuxue" c "\n yuwen" d "\n xiefangcha" cc
}


